Two Metro employees and a contract worker were rushed to the hospital after crews were doing weekend work on the red line. The contractor, identified as 41-year-old Harold Ingram of New Jersey, died at the hospital.

Metro says welding equipment ignited hydraulic fluid that was leaking from a vehicle or other equipment causing an explosion.

But Metro says that's not what killed the Ingram or injured the employees. They say the workers were struck by a 40-foot rail.

DC Councilwoman Muriel Bowser is also a WMATA's board member:

"We know a lot of hard working men and women are putting their lives on the line every day. I'm just very sorry to have learned about this incident but we'll work with my colleagues on the board and all of the staff at Metro who are heartbroken, as well, to get to the bottom of this."

The accident happened in a Metro tunnel near the Union Station Station platform on the Red Line. A portion of the line had already been shut down this weekend for track work.

The Red Line is the oldest and busiest in the entire transit system and some would argue the most troublesome. Crews were working as part of the transit's five billion dollar capital improvement program.

In 2010 two workers were killed by a piece of rail equipment near the Rockville Metro stop.

This past May fire erupted underneath a rail car at the Silver Spring Metro Station.

Metro has seen several derailments on the Red Line including one in August near the Rhode Island Avenue station and hardly anyone can forget the deadliest in the transit system's history back in 2009.

Bowser, "We know we are undergoing major track work on the red line and that's why we have the weekend closures. It is dangerous work and these workers are going into the system, all over the system so we can get it in the good state of repair that customers deserve."

Metro says track work and the investigation will be complete in time for the morning's rush.

Metro has notified both the Tri-state Oversight Committee (TOC) and the National Transportation Safety Board (NTSB).